This invention was made with Government support under a contract awarded by the U.S. Department of Energy. The Government has certain rights in the invention.
The present invention is directed to the deployment of submersible mixers in a tank, and more particularly to a self-anchoring mast for deploying a high-speed submersible mixer in high-level waste (or other industry) tanks to allow the contents to be agitated for processing or transfer.
Installation of submersible mixing or agitation equipment in tanks usually requires internal attachment and/or support structures, within the tank, to affix the mixer to the tank wall or floor. This is particularly true when high-energy machines, such as the 50 HP Flygt mixer are installed, in order to safely anchor the unit, to remain stable under the machine""s 1,600 pounds of reaction thrust from a high speed (860 RPM) propeller. If the tank is not originally built with the necessary anchoring systems, personnel must enter the tank to install the anchoring systems. Otherwise, high energy mixers cannot be considered without some other (external) support structure. In hazardous industrial tank applications, such as chemical, volatile or radioactive tanks, this factor alone often precludes high energy mixer installation or requires extensive external support systems.
Further, it is often found that deployment of smaller scale agitation equipment is attempted in a tank with the use of cumbersome and expensive tank top superstructures to support the agitator and to provide reaction capability for the mixer""s thrust. In case of large units, such as the 50 HP/1600 pounds thrust of a rotating mixer mast assembly (and larger units), the extremely large bending moment created by the mixer thrust reacted through a 40 to 45 foot moment arm, make the forces and required superstructures prohibitively large and expensive. For example, the 1,600 pound thrust of the subject unit reacted through a 45 foot tank top structure would require a mast and tank-top superstructure capable of resisting a bending moment of more than 72,000 pounds (without a safety margin) before the unit could be expected to remain stable within the tank. Similar large scale superstructures for full scale waste tanks cost hundreds of thousands of dollars to millions of dollars to design and install when related factors, such as structural loading, tank and superstructure codes and hazard ratings, seismic and other natural phenomena design are taken into account.
Masts built for radioactive waste tank deployments also require incorporation of a segmented design to facilitate removal of top sections for temporary radiological containment packaging for eventual reuse or final disposal.
Therefore, there is a need in the industry for a mast which is self-anchoring and can be quickly deployed in a tank without having to provide support components internally or external to the tank.
The principal object of the present invention is to provide a self-anchoring mast for deploying a high-speed submersible mixer in a tank which can be quickly deployed, for example, within 30-60 minutes, in a tank with no prior fixtures, supports or other attachments needed within the tank to anchor it for operation.
An object of the present invention is to provide a self-anchoring mast for deploying a high-speed submersible mixer in a tank which is preferably about 7,000 pounds center-loaded and allows a high energy mixer, such as a 50 HP mixer, to be lowered into a tank while properly anchoring the entire mast system against the mixer thrust. Smaller mixers with lesser reaction thrust can also be deployed by using similar lighter masts, and larger masts may be used for larger or more powerful mixers, both without the requirement of fixed internal anchors or supports within the tank. In summary, the mast of the invention can be easily used as a tool for installing or deploying small to high energy mixing systems. Another object of the present invention is to provide a self-anchoring mast for deploying a high-speed submersible mixer in a tank which deploys vertically through tank-top openings as small as twenty-two inches.
Yet another object of the present invention is to provide a self-anchoring mast for deploying a high-speed submersible mixer in a tank wherein the mixer can operate vertically and be remotely repositioned within the tank for horizontal discharge.
An additional object of the present invention is to provide a self-anchoring mast for deploying a high-speed submersible mixer in a tank wherein the mixer can be remotely raised and lowered to operate at any level within the tank.
Yet an additional object of the present invention is to provide a self-anchoring mast for deploying a high-speed submersible mixer in a tank which does not require any tank top superstructure.
Still yet an additional object of the present invention is to provide a self-anchoring mast for deploying a high-speed submersible mixer in a tank in which a motorized tank top rotation system allows a user to set the rate and sweep angles of up to 360xc2x0.
Still yet an additional object of the present invention is to provide a self-anchoring mast for deploying a high-speed submersible mixer in a tank which can be quickly installed or removed from the tank with a portable crane.
A further object of the present invention is to provide a self-anchoring mast for deploying a high-speed submersible mixer in a tank which allows effective and efficient agitation of the tank contents by allowing the mixer to be periodically reoriented and/or rotated to direct the mixer discharge to different areas or zones of the tank. The rotation capability allows a single mixer to mix more areas of each tank. Further, the xe2x80x9csweepxe2x80x9d angle of rotation, as well as the speed of sweep or rotation, are easily variable in order to focus mixer discharge on certain areas of the tank and to help coordinate single or multiple mixers in a larger tank with each other and with the overall fluid motion in the tank.
In summary, the main object of the present invention is to provide a mast for deploying a high-speed submersible mixer in a tank which is self-anchoring and allows the mixer/mast assembly to be quickly deployed in the tank with no prior fixtures, supports or other attachments needed within the tank to anchor it for operation.
In accordance with the present invention, a self-anchoring mast for deploying a high-speed submersible mixer in a tank, includes a first (or upper) mast member, a second (or lower) mast member operably connected to the first mast member, and a foot member operably connected to the second mast member for supporting the mast in a tank.